PURPOSE: This study examined the effects of flexible flatfeet on the accuracy of knee joint motions in closed and open kinetic chain tasks. METHODS: Twenty-four healthy participants were recruited for this study. The subjects were divided into two groups using a navicular drop (ND) test: flexible flatfoot group (n=12, male: 6, aged 22.00±2.22 years) and age-matched control group (n=12, males: 6, aged 22.17±1.53 years). The accuracy of knee motion was measured quantitatively by tracing through the flexion and extension motion of the knee joints in the closed kinetic chain and the open kinetic chain. RESULTS: There was a significant difference in the accuracy index between the groups in closed kinetic chain task, but there was no significant difference in the open kinetic chain task. In addition, there was a significant difference in the accuracy index between the closed kinetic chain and the open kinetic chain task in the flexible flatfoot group. In addition, a significant negative correlation was observed between the ND and accuracy index in the closed kinematic chain task, but there was no significant relationship between the ND and accuracy index in the open kinematic chain task. CONCLUSION: Flexible flatfeet can affect the accuracy of the adjacent joints, such as the knee joint in the closed kinematic chain.
Flatfoot ; Healthy Volunteers ; Humans ; Joints ; Knee Joint ; Knee ; Male

Anaplastic large cell lymphoma (ALCLs) are a group CD30-positive mature T-cell lymphomas, an uncommon subtype of non-Hodgkin lymphomas, characterized by diverse clinical and genetic features. Among the types of ALCL, anaplastic lymphoma kinase (ALK)-negative ALCL, though typically involves the lymph nodes, can infrequently invade other tissues. When soft tissue involvement occurs, it may mimic the clinical presentation of infectious diseases, leading to potential misdiagnosis. Therefore, a histological examination is necessary to differentiate between ALK-negative ALCL and similar phenotypes associated with infectious conditions. This paper reports a case of ALCL, initially misdiagnosed as an infection.